While caffeine is one of the key ingredients in energy drinks it can be hard to tell how much they contain. Consumer Reports just conducted lab tests on dozens of the top-selling drinks.
Everyone from Tim Tebow to 50 Cent and Joan Rivers are advertising energy drinks. With their Facebook pages and Internet video campaigns, manufacturers specifically target young people. But experts at Consumer Reports say you have to be careful how much caffeine you drink.
"It can quicken your pulse, cause abnormal heart rhythms, keep you from sleeping well, and elevate your blood pressure," said Consumer Reports Deputy Health Editor Gayle Williams.
Consumer Reports analyzed the caffeine content of 27 top-selling energy drinks, testing three samples each. Although some products list the amount of caffeine on the package, they're not required to. Consumer Reports found the numbers can be way off.
"Some of the energy drinks underestimated the amount of caffeine listed on the label by 20 percent or more," said Williams.
So how much caffeine do energy drinks contain? In laboratory tests, it varied widely.
For example, FRS Healthy Energy averaged 17 milligrams per container. Red Bull and SK Street King Energy averaged about 80 milligrams. 5-Hour Energy shots contained 215 milligrams, and Extra Strength 5-Hour Energy contained 242 milligrams.
Most healthy adults can consume up to 400 milligrams of caffeine a day.
"So for many people, an occasional energy drink is probably OK," said Williams.
Or you can drink regular coffee. An 8-ounce cup contains roughly 100 milligrams of caffeine.
Consumer and scientific groups have urged the FDA to require companies to disclose caffeine levels, but the agency says it lacks the authority to do so.
Many energy drinks do carry warnings that they are not for children, women who are pregnant or nursing, or people sensitive to caffeine.